It is known that cultures of basidiomycete have properties of BRM (Biological Response Modifiers) such as immunopotentiation, immunological activation, or macrophage activation.
Also the present inventors have filed a patent application on an agent for recovering productivity of cytokines such as human monocyte interferon gamma (IFN-γ), or interleukin 12 (IL-12) using a culture of basidiomycete (a fungus belonging to Basidiomycetes) (Japanese Patent Application No. Hei 11-283223).
The physiological activities contained in such a culture of basidiomycete have been disclosed in “Water-soluble lignin” (Examined Japanese Patent Publication No. Hei 6-88909), “Complex of cyctokinin based active substance composed mainly of polysaccharide and zeatin-related substance” (Examined Japanese Patent Publication No. Sho 62-36009), novel polysaccharide substances (Japanese Patent Application Laid-open No. Hei 8-259602) and so forth. As shown in these applications, basidiomycete cultures may contain several types of physiologically active substances. However, none of the physiologically active substance has been identified by the structure in such a manner that the existence thereof can be unambiguously confirmed by instrumental analysis, in particular a spectroscopic method (including nuclear magnetic resonance or the like).
In conventional methods, plant tissue materials have been used, so that the cultures contain various types of organic substances. Furthermore, little information on the structure of target compounds is available. This makes it difficult to distinguish the fraction containing the target substance by instrumental analysis even if separations means such as column chromatography is used. Therefore, it has been difficult to efficiently isolate and produce the component having excellent physiological activity.